| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 58/82] proc: Avoid mixing integer types in mem_rw() | Date | Mon, 26 Jul 2021 17:38:58 +0200 |
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From: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
[ Upstream commit d238692b4b9f2c36e35af4c6e6f6da36184aeb3e ]
Use size_t when capping the count argument received by mem_rw(). Since count is size_t, using min_t(int, ...) can lead to a negative value that will later be passed to access_remote_vm(), which can cause unexpected behavior.
Since we are capping the value to at maximum PAGE_SIZE, the conversion from size_t to int when passing it to access_remote_vm() as "len" shouldn't be a problem.
Link: https://lkml.kernel.org/r/20210512125215.3348316-1-marcelo.cerri@canonical.com Reviewed-by: David Disseldorp <ddiss@suse.de> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Souza Cascardo <cascardo@canonical.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Helge Deller <deller@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> --- fs/proc/base.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/proc/base.c b/fs/proc/base.c index 005d4cb2347e..5f68454cf421 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -841,7 +841,7 @@ static ssize_t mem_rw(struct file *file, char __user *buf, flags = FOLL_FORCE | (write ? FOLL_WRITE : 0); while (count > 0) { - int this_len = min_t(int, count, PAGE_SIZE); + size_t this_len = min_t(size_t, count, PAGE_SIZE); if (write && copy_from_user(page, buf, this_len)) { copied = -EFAULT; -- 2.30.2
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